We are developing a new technology for identifying dementing brain disorders, including Alzheimer's, Huntington's, and Parkinson's and for differentiating them from other mental disorders. Our method is based on detecting the olfactory deficits that are diagnostic of the dementing diseases. We will build a hand-held, solid-state, precision olfactometer for the clinician's office. By combining ink-jet microfluidics with semiconductor microfabrication techniques, we will create compact "odor-ROM chips" each holding thousands of individual odor samples. On-chip electronics will dispense single samples in a programmable, digital, interactive format. One dispense will give a single, precisely-controlled "cloud" of odoriferous vapor in the subject's airstream: multiple simultaneous dispenses (up to 10 KHz) will give different intensities, temporal patterns, or odor mixtures. MicroFab's technology dispenses low picoliter volumes with exquisite spatial, volumetric, and temporal precision. Both clinical diagnostics and basic research will be advanced by this new technology. Research on smell has always been handicapped by the problem of managing the stimulus. Our solid-state system will remove this barrier, opening new vistas in basic olfactory research and clinical diagnostics. PROPOSED COMMERCIAL APPLICATION: A research-caliber olfactometer based on microdispensing technology could replace all systems now in use for research on olfaction. Basic and applied researchers studying olfaction would all be potential customers. Our hand-held, "office-style" diagnostic unit would be targeted for use in the neurologists, psychiatrist, or general physician's office for early screening of patients at risk for dementing diseases.